No, it is not mandatory to apply for Round 1 of COMEDK counselling. You can directly apply for Round 2, even if you didn't participate in Round 1.

COMEDK conducts multiple counselling rounds to fill up the available engineering seats in participating colleges.

Not mandatory to participate in all rounds: You can choose to participate in any round(s) that suit you.

Round 2 is for those who:

• Didn't get a seat in Round 1.
• Missed Round 1 altogether.
• Want to explore better options in Round 2 (might have seat availability changes).
  
  https://engineering.careers360.com/download/ebooks/comedk-a-complete-guide
  
  I hope it helps!